Jada has been helping her younger brother practice his math facts all week. Each time they practice, Jada gives her brother 3 minutes to do as many math facts as he can. On Monday, Jada's brother completed 48 math facts. On Tuesday, he did better and completed 57 math facts. How many more math facts per minute did Jada's brother complete on Tuesday than on Monday?
Write your answer as a decimal or a whole number.